Circular saw for splitting animal carcass

ABSTRACT

An automated and manually-operative carcass-splitting apparatus is disclosed. Enhanced alignment of a centerline of a carcass with a circular blade of a saw assembly is provided. The carcass is suspended by hooks on a continuously moving conveyor system. Indexing permits selective engagement between a station&#39;s frame and the moving conveyor. The station simultaneously moves horizontally while it descends in concert with the horizontal movement of the carcass. A hydraulically-driven suspension mechanism pivotably suspends a fluid-powered saw with freedom for several directions of manually-controlled movements during carcass cutting.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an improved automated carcass splittingapparatus for use in animal slaughterhouses abattoirs and the like.

2. Background Discussion

Previously known devices for handling and splitting animal carcasseshave comprised a wide variety of automated or semi-automated systemswhich are generally suitable for handling one specific type of beast orbeasts of similar dimensions and characteristics i.e. beef and horsecarcasses or pig and sheep carcasses. Amongst the splitting sawshitherto available have been electrically operated circular saws,electric or hydraulic reciprocating saws, band saws or pneumaticpercussion cutters. Generally speaking, electric circular saws arepreferred for splitting beef carcasses while a pig carcass splitter mayoften comprise pneumatically driven dual chopping blades driven downeither side of the backbone. A reciprocating saw fitted with choppingblades has found limited acceptance as a splitter suitable for a widerrange of animal carcasses.

In general the electric circular saw has been found to be the mostsuitable carcass splitting saw in view of its speed (about 10 secondsfor any beast compared with variable times up to 20 seconds for areciprocating saw depending on the size of the carcasses. Electriccircular saws are generally simple in construction and thus have lowmaintenance requirements and at the same time permit easy and economicalblade sharpening. Further there are traditional labour savings in use ofa circular saw due to its speed of operation and ease of use which arereflected in labour piece rates applicable to slaughter flooroperations. The use of a circular saw necessitates less spreading of thecarcass in view of its relatively thin blade compared with those ofreciprocating or band saws. Of the prior art saws, only the circular sawhas been found particularly suitable for automated systems wherein thesaw station is able to traverse with a carcass on a moving conveyor tosplit the carcass at a set speed.

Although to date electric circular saws have been considered mostsuitable for automated systems, they suffer a number of seriousdisadvantages. Electric circular saws of this type generally comprise apair of 7.5 or 10 horsepower electric motors mounted on either side ofthe saw blade on a common shaft. Such saws generally weigh in the regionof a half tonne which necessitates very complex suspension systems topermit free movement of the saw. The saws are cumbersome to use becauseof their weight and bulk in addition to the suspension system. The largerotational mass of the saw gives rise to gyroscopic effects whichseverely limit free movement and the starting and stopping torqueapplied to the electric motors can cause "kick-back" which is not onlydifficult to control and dangerous for the saw operator but also causesundue strain on the suspension system. For safety reasons and the sakeof efficiency, it is required to be able to stop the rotation of the sawblade immediately after the carcass splitting operation is completed.This is usually achieved by the provision of a plugging contactor whichreduces or even reverses the polarity of the motors momentarily. Thisplaces enormous strain on the electrical and mechanical components ofthe saw motors. Other problems associated with electric circular sawsare:

1. Limited depth of cut available due to bulk of motors-- this cannecessitate use of large blade diameters for large beasts.

2. Very high noise pollution particularly during starting and stoppingoperation. Under certain cutting conditions, harmonic frequencies of theblade itself can contribute greatly to noise pollution.

3. Lack of speed control to avoid harmonic frequencies in the saw blade.Speed control is also important during washdown and sterilization of theblade. At high speeds wash liquid spray and waste material throw-off cancause a health hazard due to contamination.

4. Sterilization has been considered a problem with this type of saw dueto the need to completely contain the saw blade during washdown betweencarcasses. Complete containment is necessary due to lack of speedcontrol and need to protect motors from ingress of washing liquid.

5. Due to the problems of the weight and bulk of electric circular sawsand their suspension systems together with the operational difficultiesof "kick-back" and the gyroscopic effects, it has become common practiceto mount the saw on a rigid suspension system. The saw is able to travelvertically on the rigid suspension system but it is necessary tocarefully align the carcass with the saw blade to permit accuratesplitting. This is usually achieved by indexing the carcass to a pointadjacent the saw then either stopping the conveyor system ordisconnecting the carcass suspension hook from the conveyor, thenspreading the hind legs to facilitate easy splitting. After splitting,the carcass sides are then indexed back into the conveyor system by asuitable mechanism.

SUMMARY OF THE INVENTION

It is an aim of the present invention to provide a carcass splittingapparatus which overcomes or substantially alleviates the abovementioneddisadvantages.

According to one aspect of the invention there is provided an animalcarcass splitting saw means comprising:

an hydraulic or pneumatically operated circular saw;

control means to selectively control the speed of rotation of said saw;and,

suspension means to permit in use substantially free movement of saidsaw for alignment with a carcass.

Preferably said suspension means comprises a frame attached to said saw,said frame adapted for pivotal connection to a support frame.

Preferably said suspension means includes selectively controllableelevating means whereby in use said saw may be selectively elevatedrelative to a datum.

Preferably said selectively controllable raising and lowering meanscomprises an hydraulic or pneumatic cylinder.

According to another aspect of the invention there is provided an animalcarcass splitting apparatus comprising:

an operating station selectively elevatable on a substantially uprightaxis;

a saw means substantially as hereinbefore described, said saw meansadapted for suspension from said operating station; and ,

means to selectively move said operating station along an axis which issubstantially transverse to the initial upright axis.

Preferably said operating station comprises a first frame meansassociated with a second frame means and is adapted for elevation on asubstantially upright axis therewith.

Preferably said means to move said operating station along asubstantially transverse axis comprises means to move said second framemeans along a substantially transverse axis.

Preferably said second frame means is adapted for movement along asubstantially transverse axis adjacent to and substantially parallel toa conveyor means, and second frame means including means to permitoperative association with said conveyor means whereby in use, saidsecond frame means is permitted at least limited travel in associationwith said conveyor means.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of each aspect of the invention will now bedescribed with reference to the accompanying drawings in which:

FIG. 1 illustrates a front elevation of a carcass splitting saw means.

FIG. 2 is a side elevation of the saw illustrated in FIG. 1.

FIG. 3 is a top plan view of the saw of FIGS. 1 and 2.

FIG. 4 is a front elevation of a carcass splitting apparatus accordingto the invention.

FIG. 5 is a side elevation of the apparatus shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1 the saw comprises a frame 1 constructed of hollowsquare-section steel tubing with a support bracket 2 mounted atopthereof. An hydraulic motor 3 is attached to one side of the frame byany suitable means and is arranged such that the circular saw blade 4 isdisposed substantially centrally of the frame 1. A safety guard 5 ismounted on the rear of the frame to protect an operator when the saw isin use. The guard is suitably of channel section and is disposed overapproximately one half of the perimeter of the saw blade. Operatinghandles 6 are suitably mounted on either side of the frame to facilitateuse of the saw. To counterbalance the weight of the hydraulic motormounted to one side of the frame, a counterbalancing weight is requiredon the other side of the frame. This may be suitably achieved byplacement of scrap lead or lead shot 7 within the hollow interior of theother side of frame 1. Alternatively a counterweight may be attached tothe exterior of the frame. Counterbalancing of the saw motor permits thesaw blade to be oriented essentially vertically when the saw arrangementis suspended from bracket 2.

A guard 8 is preferably mounted over the front and upper part of motor 3to facilitate cleaning and to prevent, in the event of leaking hydraulicjoints, contamination of a carcass during the splitting operation.

FIG. 2 is a side elevation of the arrangement shown in FIG. 1 from whichit can be seen that the saw motor is mounted on suitable brackets 9forwardly on the frame 1. The operating handles 6 are also mountedrearwardly of frame 2 on suitable brackets 10. The rearwardly disposedhandles permit ease of operation of the saw by an operator and theforward disposition of the motor permits greater access to the carcassto ensure maximum depth of cut of the blade. Suspension bracket 2 isprovided with a number of apertures 11 to facilitate suspension of thesaw.

FIG. 3 is a top plan view of the saw illustrated in FIGS. 1 and 2.

FIG. 4 illustrates a front elevation of a carcass splitting apparatusaccording to the invention. A first frame 11 comprising a platform 12and a three sided enclosure 13 is attached to a second frame 14 foressentially vertical movement within guides (not shown) on frame 14.Vertical movement of frame 11 is achieved by hydraulic cylinders (notshown) mounted on the rear face of the second frame and attached toframe 11. Frame 11 further includes an upper cross beam 15 mounted onuprights (not shown) located within the guides on frame 14. Mountedunderneath cross beam 15 is a rail 16 at substantially right anglesthereto. Rail 16 supports a moveable carriage 17 slung from which is anhydraulic cylinder 18 which suspends the saw arrangement as hereinbeforedescribed. Frame 14 is mounted at its upper and lower ends 19 and 20respectively on rollers 21 and 22 respectively which coact with rails 23and 24 respectively. Rails 23 and 24 are arranged in parallelrelationship with a carcass conveyor system 25 spaced from frame 14.

FIG. 5 illustrates a side elevation of the apparatus illustrated in FIG.4 with frame 11 elevated to its uppermost position by hydrauliccylinders 26. With the frame 11 in the elevated position, an operatorstanding on platform 12 can commence splitting of the carcass 27suspended by a suitable hook arrangement 28 from conveyor system 25.

Mounted on a subframe 29 or other suitable attachment means is anindexing means 30 which permits selective engagement between frame 14and conveyor hook 28 or other moveable conveyor component. The indexingmeans preferably comprises a pneumatically actuated finger. The indexingmeans 30 on engagement with say a conveyor hook 28 moving along conveyorsystem 25 permits alignment of a carcass substantially with thecentreline of the blade of the saw assembly while simultaneously drawingframe 14 along its upper and lower tracks 23 and 24. This cooperativemovement permits a saw operator to split the carcass while frame 14moves in concert with the carcass on the conveyor. On completion of thecarcass splitting operation, frame 14 is returned to its initialstarting position by a pneumatic cylinder 31 mounted adjacent the floorand connected to the frame 14 by a bracket 32 or other suitable means.

In a preferred embodiment of the invention the pneumatic and hydrauliccontrols for the saw motor 3, the elevating cylinder 18, the indexingmeans 30 are arranged on frame 11 adjacent the saw either on the sawframe or handles 6 or on a panel attached to the frame 11. Thesecontrols permit selective manual operation of each of the abovefunctions.

The pneumatic controls for disengaging the indexing means from theconveyor and for returning frame 14 to its initial postion arepreferably automatically controlled by suitable pneumatic or solenoidswitching valves but manual override controls are also provided on frame11. As a further safety feature, pressure sensitive electric switchingmeans may be provided to prevent overrun of frame 11 or frame 14 ineither direction or to stop the conveyor in the event of an emergencysituation.

Further additional features which may be incorporated in the preferredembodiment are brake means for the saw blade such as a hydraulically orpneumatically operated disc brakes. The controls for the brake means maybe manually or automatically operable when hydraulic power is removedfrom the saw. Saw washing means may also be included within enclosure 13for washing and disinfecting the saw and blade between each splittingoperation. The washing means may be positioned on an interior wall ofenclosure 13 or associated for example in the form of jets, with the sawframe. Preferably a sliding or pneumatically retractable door isprovided to close the aperture in the three sided enclosure 13 toprevent splashing of washing solution or waste material during the sawwashing operation.

The operation of the apparatus according to the invention will now bedescribed. From an initial starting position with a freshly washed sawarrangement, the operator manually activates hydraulic cylinders 26 toelevate frame 11 (hereinafter called the work station) to its maximumheight above floor level whereupon the elevating action of cylinders 26is deactivated automatically. The operator then activates the indexingmeans 30 to cooperate with the conveyor when a carcass is indexedsubstantially centrally of the work station. Simultaneously, theoperator actuates the saw mechanism and advances the saw via carriage 17towards the uppermost end of the carcass. When the saw is suitablyaligned with the carcass the operator activates the hydraulic circuitconnected to cylinders 26 to cause the work station to advancedownwardly, the saw splitting the carcass during the downward motion. Ifdue to the size of the carcass, the normal travel of the work station isinsufficient to permit complete splitting of the carcass, the operatorcan then activate saw suspension cylinder 18 to obtain a limited amountof further travel. On completion of the splitting operation, theoperator withdraws the saw from the carcass and activates the bladebrake. Simultaneously the operator can operate pneumatic cylinder 31 anddisengage the indexing means 30 by an override switch to return frame 14to its original position. Alternatively the operator can wait until theframe 14 reaches the limit stop switches whereupon the indexing means 30is disengaged from the conveyor and the frame 14 is returned to itsinitial position by pneumatic cylinders 31. During the return travel offrame 14 to its initial position, the work station is lowered to itsinitial position at which washing of the saw assembly can be achieved.

The saw assembly of the present invention offers particular advantagesin its ease of cleaning which is facilitated by controllable slowrotation of the saw blade.

The controllable speed of rotation of the blade permits an operator toavoid excessive noise from the saw blade when harmonic frequencies arereached, simply by altering the speed of rotation of the saw blade to agreater or lesser degree. In an alternative embodiment, the hydraulicdrive means can be coupled to a known speed controller whereby motortorque is automatically adjusted for varying loads to maintain aconstant speed of rotation. By this means, one or more predeterminedrotational velocities can be chosen to take into account factors whichcontribute to generation of excessive noise levels.

It will be readily apparent to a skilled addressee that manymodifications or variations may be made to the invention withoutdeparting from the spirit and scope thereof.

I claim:
 1. An animal carcass-splitting apparatus suitable for use witha continuously moving carcass conveyor, said apparatus comprising:asupport frame movable along guide means parallel to the direction ofmovement of a continuously moving carcass conveyor; an operating stationmovably mounted on said support frame for selective elevation on anupright axis to an initially elevated position; means for selectivelyelevating said operating station and said circular saw on an uprightaxis; indexing means for selective engagement between said support frameand a movable conveyor component to enable automatic in-use movement andcontrolled descent of said support frame in concert with a carcasssuspended from said conveyor; a fluid-powered circular saw suspendedfrom said operating station for selective elevation therewith relativeto said support frame; and said circular saw suspension meanscharacterized as manually movable through several directions of movementfor operator-controlled alignment with the center line of the movingcarcass to be split.
 2. An apparatus as claimed in claim 1 wherein saidindexing means additionally comprises:an extensible member mounted onsaid support frame for selective engagement or disengagement with amoving carcass suspension member on said conveyor whereby in use saidsupport frame is drawn along said guide means by the operation of saidconveyor.
 3. An apparatus as claimed in claim 2 and further comprising:alimit switch means mounted on said guide means to limit the extent oftravel therealong of said support frame, said limit switch means, whenactuated, operative for retracting said indexing means from said movingcarcass suspension member and further operative for actuating afluid-powered ram assembly tfo return said support frame to an initialposition on said guide means.
 4. An apparatus for splitting of beefcarcasses suspended from a continuously moving conveyor, said apparatuscomprising:a first support frame movable on upper and lower guide railsparallel to said continuously moving conveyor; an operating stationmounted for vertical elevation on said support frame; a fluid-poweredcircular saw mounted on said operating station for vertical movementtherewith; an extensible indexing member mounted on said support framefor selective engagement with a carcass suspension means moving on saidconveyor whereby said support frame is urged along the guide rails bythe movement of the conveyor; a limit switch mounted on said guide railsto limit the extent of travel of said support frame by disengaging saidindexing member from said moving carcass suspension means, said limitswitch also actuating a fluid-powered ram to return said support frameto an initial position on said guide rails; and operator control meansmounted on said operating station for actuating automatic elevation ofsaid operating station to a predetermined height, actuating saidindexing member when said operating station is at said predeterminedheight, actuating said circular saw and also actuating said operatingstation for automatic descent at a predetermined rate.
 5. An apparatusas claimed in claim 4 and further includingoperator override controls tooverride said predetermined limit of travel as indicated by said limitswitch.
 6. An apparatus as claimed in claim 4 wherein said circular sawfurther comprises:speed control means for selectively varying the speedof rotation of a saw blade of said saw to reduce operational noiselevels created by harmonic frequencies in the saw blade.
 7. An apparatusas claimed in claim 6 wherein said circular saw is operable at very lowspeeds to facilitate washing of said circular saw blade between eachcarcass-splitting operation in an open environment without the need foran antisplash enclosure.
 8. An apparatus for splitting of beef carcassessuspended from a continuously moving conveyor, said apparatuscomprising:a continuously moving conveyor for moving carcasses to besplit; a first support frame movable on upper and lower guide railsparallel to said conveyor; an operating station mounted for verticalelevation on said support frame; a fluid-powered circular sawsuspendably mounted on said operating station for vertical movementtherewith; an indexing means mounted on said support frame for selectiveengagement with a carcass suspension means moving on said conveyorwhereby said support frame is urged along the guide rails by themovement of the conveyor; operator control means mounted on saidoperating station for actuating the elevation of said operating stationto a predetermined height, actuating said indexing member when saidoperating station is at said predetermined height, actuating saidcircular saw and also actuating said operating station for automaticdescent at a predetermined rate; and hydraulically-driven suspensionmeans pivotably mounting said fluid-powered circular saw from the upperportion of said operating station and responsive to manual control formultiple direction of movement, including laterally into and out of saidcarcass during splitting, downwardly an additional vertical amountrelative to said station and from left to right for following curves andtwists in the spine of said carcass.